According to the American Cancer Society, in 2009, there were approximately 20,000 deaths in the United States from malignant brain tumors. The most aggressive of these tumors, Grade III and IV malignant glioblastoma multiforme (GBM) is particularly resistant to treatment. A patient receiving a diagnosis of a GBM will most likely die within just a year or two; the median survival rate is about 12 months, regardless of treatment. Today, the stark finding is that treatment options are limited and there is no obvious silver bullet on the horizon. However, amidst the complexities of the disease and the ongoing efforts poured into current surgical, radiation, and chemotherapy treatments, there is a growing technical, and clinical rationale for pursuing targeted drug delivery directly to brain tumors as a next-generation therapy. In this approach, the objective is to deliver the right therapeutic agent (e.g., conventional small molecule chemotherapy drug, large molecule biologic drug, nanoparticle, or perhaps even virus vector) to the correct brain region, at the most efficacious times and at the most efficacious dosage, all while not damaging normal brain tissue and maintaining patient safety and quality of life. This is a difficult, largely unsolved problem due to the critical intrinsic complexities of the tumor-brain system and interfacing with it, including complex and highly variable tumor morphology, composition, and mass transport, and complex technologies required for sophisticated implantable drug delivery devices.
One of the promising new treatments is referred to as convection-enhanced delivery (CED). In this approach, cancer-fighting drugs are directly infused under pressure into the tumor using an implanted catheter. CED is attractive because (1) it bypasses the blood-brain-barrier (BBB) and the systemic vascular system to deliver chemotherapeutic agents directly into the interstitial space of the parenchyma and (2) it uses external pressure to supplement the slow mass transport achieved by diffusion and achieve a degree of infusion control. However, a fundamental problem with clinical CED to-date is that current catheters and injection methods have not been sufficient to overcome the critical intrinsic complexities of targeted drug delivery to tumors (such as complex tumor morphologies, and non-homogenous and dynamic hydrostatic and mass transport characteristics), nor to address the need for precise control of drug concentrations over time (days) and space (centimeters) in tumor, brain, and interstitial volumes. Quite simply, CED drug delivery technologies have not kept pace with CED application requirements.
Thus, there is a need in the medicine field to create an improved neural drug delivery system. This invention provides such an improved neural drug delivery system.